Method of backing electrotype plates



July 1o, 192s. 1,676,628 H. M. BLAETz METHOD OF BAGKINGELECTROTYPE'PLATES Filed Nov. v. 1924 4 sheets-sheet' 1l Y l.IlllllllllllllIllllllllllillllll H. M. BLAETZ METHOD- OF BACKINGELECTROTYPE PLATES July 10,

July l0, 1928. l ,676,628

Y v H. M. BLAETz METHOD 0F BACKING ELECTROTYPE P LATES Filed NOV. '7,1924 4 Sheets-Sheet 3 I I I I I A i x lllllilllllxllllllll July 1o,192s.

Filed Nov. '7, 1924 4 Sheets-Sheet 4 Patented July 10, 1928.

UNi'iEo stares PATENT OFFICE.

HARRY M. BLAETZ, OF PHILALELPHIA, PENNSYLVANIA, ASVSIGNOR TO ROYAL ELEC-i TROTYPE COMPANY, OF PENNSYLVANIA.

PHILADJELITIPHIA,4 PENNSYLVANIA, A CORPORATION vOF Application filedNovember 7, 1924. Serial No. 748,428.

My invention relates to backing electrotypes by pouring molten backingmetal upon the tinned backs of the plates. t

The purpose of my invention is to provide a process and a machinefor'obtaining a backing free from air-holes and of homogeneous densityand shrinkage throughout.

A further purpose is to greatly reduce danger of failure of plates inthe printing press by reason of hidden blowfholes, and to reduce thethickness required initially for the backing because' less shaving needbe done in the final finishing operation.

A further purpose is to greatly straighten the plate7 take out thewrinkles and level its surface, and generally to reduce the handfinishing which is required.

A further purpose is to strengthen and toughen the material of the plateand particularly that part closest to the electrotype- A further purposeis to secure the greatest yaccuracy of registration of differentelectrotypes from the sameV original plate by the faithfulness withwhich each copy is made to agree with the original.

A further purpose is to drive out parti-A cles of air from between thetinned electrotype and the backing by striking the' bottom of the pan inwhich the electrotype lies progressively while the backing is stillmolten.

gressive blows Vmore effective by having them cushioned or dead. t w

A further purpose is to strike blows progressively over the bottom ofthe pan and at the same time to press a grid upon the top of thebacking. v

A further purpose is to press a grid resiliently into the backing whilethe latter is still molten or nearly molten to prevent.

substantial creeping of the metal during its period of most rapidshrinkageduring solidiiication and during cooling from near its point ofsolidification.

A further purpose is to provide an inexpensive machine adapted to carryout my process.

'fication and in the claims.

I prefer to illustrate my invention by several varieties only of asingle form, selecting one which well illustrates the principles of myinvention. j

Figure 1 is a top plan view of a form of structure capable of carryingout my invention.

Figure 2 is a section upon line 2 2 of Figure 1.

.Figure 3 is a Figure 2. l

Figure 4 is a fragmentary side elevation of a grid seen in Figures 1, 2and 3.

Figure 5 is a fragmentary bottom plan view of the grid of Figure 4. i'

section upon line 3 3 of Figure 6 is a fragmentary top plan view p of atray seen in Figures 1, 2 and 3.

Figure 7 is a fragmentary section upon line 7 7 of Figure 6.

line 10-10.

Figures 11 `and 12 are fragmentary sections corresponding with Figure 9butshowi v ing the parts. in different positions. A further purpose isto make the prol.

Figures 13 and 14 are fragmentary top plan views and side elevationsshowing a modification ofthe grid holding structure, Y

pouring and evolving mechanism appearing in Figure 14. y.

Figure 15 is a tcpvplan view ofa plate backing equipment` with which myinvention may be advantageously associated.

Figure 16 is a side elevation of the struc-k tinned backs of electrotypeplates, in the best process of backing plates now known to me and laterherein described in connection with Figures -17, many of the kplates arerendered soft in spots by blow holes.

These differ greatly in size butl are ordinarily made upfof a largenumber of very fine holes. making theplate spongy and hence unfit tosupport the pressure to which the plate is ultimately to be subjected.rIhere is trouble also from the contraction of the backing parallel toits surface, which tends to compress and distort the image upon thefaces of the eleetrotype, injuringl the individual plates andinterfering with proper registration in ksets of plates intended forcolor printing.

If the blow hol-e fault be detected in time and it be not too serious,it can be. corrected during the finishing operations but at considerableexpense of time and skill and vwith a resultant inferior plate at ibest.

vcooling process.

In spite of all care there are frequent disvcards at the press fromair-holes sullicicntly [metal is stillmolten to cause the air theretrapped to pass up through the molten metal or along the lower surfaceof the metal to the edge of the plate, securing greater strength andtoughness and a very much more vlevel surface and that at the Sametimecreeping of the metal during solidilication and consequent distortion ofthe plate and undue shrinkage of the plate may be stoppedV byresiliently pressing a grid of supporting metal against the uppersurface: of the metal while it is still molten and maintaining thispressure during the Even a greatly curved electrotype can bestraightened and flattened by my process.

In the first form of my invention I have illustrated a simpleconstruction for rapping a tinned plate which has been covered with amolten backing in a tray 21 specially intended for use within a rappingmachine. The tray is rested upon any suitable supporting frame 22 of themachine anda thrust-receiving holder 25 is rested upon the top of themolten metal, being pressed upon the surface of the metal by Vsprings 24held down by a top frame 25. The pressure is exerted through a set screw26 locked in height adjustably by a nut 26. The set screw is depressedby a lever arm 27 pivoted at 28 and latched, during the rappingoperation beneath hoop: '22). The holder or cover 23 with its springsand adjustment is preferably removable in its entirety to give readyaccess to the tray.

The grid is provided with a roughened face 30 (Figures 4 and 5) toengage suliiciently with the surface of the molten metal torestrain thecontraction of the metal during that portion of its cooling when therate of contraction is greatest and the cohesion of the metal least;namely, during the earlier stages of solidification and during therelatively high contraction which ordinarily takes place -in the upperrange of temperature just below the congealing temperature. l

I find that by such roughening I can greatly reduce and well equalizethe contraction so as to relieve necessary contraction wholly from itsobjectionable features. The exact character of the rougheningof what Iterm the grid face is not material provided it will interlocksufficiently to hold against 'strain parallel tothe face in searchdirections. I illustrate projections 31 in rectangular arrangement sothat they hold against creeping both lengthwise and across the plate.The projections are exaggerated in the illustration.V

The tray, best seen in vFigures 6 and 7, is provided with flanges 33which position it with respect to the frame member 34, and with handles35 by which it maybe removed. Y

In order to drive outr trapped air from c beneath the molten metal, Itap the tray at the bottom soA as to transmit the blows to the face ofthe electrotype which' is'being backed, finding advantage not only inthe tapping itself butin a progressive advance of the tapping from thecenter toward the edges or, because of its greater convenience from oneside or end toward the other.

The inconvenience of tapping the tray immediately after the moltenbackingl has been poured makes it desirable ordinarily to tap the trayjust before the metal solidifies and I illustrate this. v

The tapping mechanism shownin Figures 1 8 comprises a plurality ofplungers 36 which operate through a guide or guides 37 to move in avertical direction and which are vthrown upwardly by springs 38 restingagainsta support 39 carried by the frame of the rapping machine. y

The plunger rods t() are guided in sup port 39 and at theirflower endsare screwed intov bars 4l and lockedtherein by nuts 42.

Each bar may control any predetermined number and arrangement ofplungers to rap lthus cover a particular Vsection of the bottom -of thetray of regular or irregular shape, so that the progress of thesuccession of lrappings may follow the law determined upon. 'In thepresent case the plungers which operate together are arranged in rowsacross the trayin order to cover or rap a portion of the length of thetray with progression successively to other portions of the length ofthe tray, each of which is rapped by a different set or row of plungers.

I prefer to use a separate spring about each plunger rod rather' than toreduce the number of springs and increase their' strength. Each bar 41,whatever the shape or section of the bottom of the tray.

to be rapped by its plunger rods, is separately drawn downwardly slowlyand quickly released. In my preferred form this is accomplished by facecams 43, engaging and drawing down pins 44 connected with the bars. Theface cams are provided with cam surfaces 45 and the pins are supportedfrom the bars by lrods 46. Obviously the cams 43 can be identical andcan be timed to any preferred order, beginning at either end orbetween'the ends, accordingl to the angular placing of the cams uponshaft 47 in bearings 48. In the form as illustrated the right' hand camof Figure 2 will engage first and therefore will release first and thecams will engage successively from right to left, so that the successionof releases will rap progressively from right to left in this figure.

Since it is best to take up all of each blow in the tray the heads 'ofthe plungers desii'ablytei'ininate in ends of fibre or other material 49to deliver non-resilient blows.

The interval between successive blows may be made'as short .as desiredby increasing the speed of the shaft whether loperated'by hand or bypower, orby increasing' the number of sets rof plungers and the hammerswhich they provide. It may also be made uniform not only within thesuccession of the set but between the last one and the first of thenext` giving not 'only uniform spacing of blows but also close approachto uniformity of torque in the driving mechanism. p Y

The driving mechanism shown in Figures 2 and 3 comprises a. handle 50. astub shaft 51 and gears 52, 53 upon the stub shaft 47 respectively. InFigure 14 shaft 47 is connected through mitre gears 54 with a shaft 47to change the angle of the driving shaft with respect to the cam shaft.

My invention would obviously be carried out in its broader aspects bythe delivery of blows to the bottom of the tray even if notprogressivelyadvancing nor successive and in the latter cases even if bya single set of hammers only upon different parts ofthe tray bottom,either the set or the tray advancing. The broad features of the gridcontrol of shrinkage likewise requires relative motion only between thegrid and the metal, whichever be moved to secure sectional interlocking.

In the form shown in Figures 9-12, the bars 41 lie beneaththe top pieceof a frame 55 by which all of the bars can be drawn down togetheragainst the tension of their springs 38 and of the frame-resettingspring 56. The frame 55 is Vdrawn down by a pedal lever 57, pivoted at58. The pedal lever is connected yby link 39 with a lever 60 pivoted at61 and connected by a bolt 62 with the frame 55.

While the lever 57 is held down the bars 41 are all locked down by meansof a plurality of concurrently movable hooks 63, 63, 632, 633, 634, 635,having different extents of overhangat 64 so as'to engage with the bars41 to differing extents. The hooks 63-635 are mounted so as to engageand release the bars with movement, here shown as horizontal, of asupport 66 which operates in guides 67 and is moved by handle 68 uponrod 69. AThe rod is threaded at 7 Opto engage with the fixed thread 71and is swivel-connected hooks are shown in Figure 11 inposition ready'for connection with the` several bars, the position assumed when thepedal lever 57 has been depressed but when the hooks have not beenbrought into hooking position with respect to thebars 41. In Figure l1,2the position'pofV the parts is shown correspending with latching of thebars in their lowered position. As will be seen. operation of the handle68` t-o move the hooks to lthe right in Figure 12 will release one afteranother, depending upon the depth of engagement of the bars with thehook members, and this depth of engagement is least at the right and isprogressive greater froi vright to left. Y p `In Figures 13 and 14 themechanism .is substantially that `of Figures 1-3, differing in using astub shaft 47 and mitre gearing 54 along with a grid holding mechanismwhich does not require the spacing lengthwise lof the machine which isrequired by the lever 27, producing a more compact machine thanv that ofFigures V1-3 butrsuffer'ing the disadvantage that the trays are not soeasily accessible for removal as are the trays of Figures 1 3. Part'ofthe plate-backing construction of Figures 15 and'16 is seen in Figure14.

with the bar 65. vThe VIn the grid holding mechanism, the bar Y 25carries a nut 72 within which is threaded screw 73 of hand wheel 74. Thescrew is swivele'd at 75 in a supporting bar 76 so that the support 23with the grids and springs may be lifted in their entirety by means ofthe hand wheel. With this construction separated grids are used tocorrehot bath 79 of molten metal.

`WithtWo grids for separate trays. The machine is located outside of andfor use in connection With a plate-backing machine in which two trays ata time are successively tinned, backed, cooled and discharged. The

rapping machine is placed close to the position of the plates when theyhave been partially cooled but before they have solidified, givingopportunity for rapping them just before their discharge.

c A very desirable layout for backing electroplates is shown in Figures15-17.v

The plates 77 are laid face down in pans 78 and these pans are placed ontop of the The backs of the plates are then coated With tinning flux andcovered with one or more thin sheets of soft tinning solder' as is wellknown.

The hot'bath almost immediately melts the thin sheets of solder coveringthe backs of the plates and raises the plates to about the temperatureof the molten backing metal.

After the backs are tinned the pans are lifted to the adjacent sectionof the turntable 80. This turntable has four sections, 8l, 82, 83 and84, Which are adapted in the positions shown successively to occupy (l)a position Where 81 is shown, adjacent to the bath 7 9, Where itreceives the trays of tinned plates, (2) a position Where 82 is locatedunder the spout 85 of the cupola 86 from which it receives moltenbacking metal and Where it is partly cooled `by a blast of air from anair pressure pipe S7, (3) the position of 83 at which the molten backsare further cooled by being subjected to a blast of air directed byanother air pipe 88 and (4f) a position at Which the backed plates 'are'removed from subsequent operations. The operations at these severalpositions take place concurrently. i

The emptied sections are successively filled with tinned plates inposition (l) are turned from that position to position (2) to receivethe backing metal and a cooling blast, are turned to position forfurther cooling and from there are turned to position for Withdrawal.

The double tray 21 is shifted in its en.-

tirety with the turntable sections to thek point of rapping ordischarge. Therapping is done preferably in a separate position astheuse of a rappinginachine to rap the bottom of the trays in situ Wouldunduly complicate the backing machine unless the gridy holding device beomitted.V

)Vherc the rapper is left in place to operate upon a turntable-supportedtray 1 prefer to use a form of rapper in Which all of the rappinghammers may be depressed at the same time or to relatively lift therapper with respect to the tray after the latter has been turned ormoved over the hammers.

Preferably as the plates come to position (3), just beforesolidification they may be transferred to my rapping machine for rappingwith subsequent direct discharge from it or retransfer to position (4).

hether the rapping machine be independent of the backing mechanism orcooperating therewith, Whether it rap one plate or more at a time andWhatever the law of the machine kas to lateral movement of the plungeror plate or the succession of the rapper Where more than `one set ofrappers is used, rapping or jarring of the under surface of the tray iseffective to reduce the air bubbles and, as to those which are left, toreduce their size.

In operation, the rapping not only drives the air along in bubbles tothe side or end of the plate or causes it to escape through the bodyofrmolten metal to that portion of the back of the plate which Will becut olf during the .planing orr shaping of the back of the plate, butthere is also a combination between this feature and the roughening ofthe back of the plate by the grid which facilitates release of thebubbles at the back of the plate. Those bubblesvvhich do not Whollyescape Will lie Within the raised portion of the metal left by theroughening.

The pressure from the grid upon the molten metal increases thecompression and therefore the pressure of any air Which is trappedWithin the metal or between it and the electrotype, increasingv thecapacity of this air to flow during the rapping process and reducing thesizeof air hole caused by any given quantity of trapped air.

A partial advantageof the rapping of the plate Will be obtained, evenWhere the air is not Wholly expelled, if it be sufficiently dissipatedand distributed so that there is no concentration of even fine airbubbles to produce spongy or soft spots in the plate, as the same sizeof air holes Which become quite objectionable in spongy spots in the'such other forms. modifications and clnei'iges as come within thereasonable spirit and scope of my invention.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is g- 1. The method of distributing oreliminating air trapped between the back face ol an electrotype and amolten backing therefor or within the backing, which consists in jarringthe electrotype after the back has been applied and before itsolidifies.

2. The method of distributing or eliminating air trapped between theback face of an electrotype and a molten backing therefor or within thebacking, which consists in jarring the electrotype by impulses from theface side of the electrotype toward the backmfr.

The method of distributing or eliminating air trapped between the backface of an electrotype and a molten backing therefmf or within thebacking, which consists in jarring the electrotype by blows deliveredfrom the face side of the electrotype and progressively spreading thearea cove-red by the blows over the face of the electrotype.

4. rlhe method of distributing or eliminatingvair trapped between theback face of an electrotype and a molten backing therefor or within thebacking, which consists in progressively rapping the electrotype atspaced distances along its surface after the backing has been appliedand before it solidifies.

5. The method of distributing or eliminating air trapped between theback face of an electrotype and a molten backing therefor or within thebacking, which consists in progressively rapping the electrotype alongits surface at a plurality of points at a time before the backingsolidifies.

6. The method of distributing or eliminating air trapped between theback face of an electrotype and a molten backing therefor or within thebacking, which consists in progressively rapping the electrotype alongits surface at a plurality of points at a time covering zonesprogressively extended to cover substantially the entireV surface of theelectrotype. 4

7. The method of distributing or eliminating air trapped between theback face of an electrotype and a molten backing therefor or within thebacking, which consists in placing the electrotype face down in vaholder, preparing the plate for intimate union with the backing,applying molten backing to the back of the electrotype and striking theholder at a plurality of points at a time while moving the electrotypeand striking means with respect to each other to progressively changethe points at which the holder is struck.

8. The method of distributing. or eliminatin-g air trapped between theback face-of 4an electrotype and a molten backing therefor lor withinthe backing, which consiste in placing the electrotype face down in aholder, preparing the plater foi-'intimate union with the backing,covering its back with molten backing metal and striking the holderdeadened blows.

9. The method of distributing or elimi-y nating air trapped` between theback face of an electrotype and a molten backing therefor or within thebacking by plungers resiliently pressed toward contact with a tray inwhich the electrotype is rested. which consists in turning the platefor-intimate union with the backing, covering the rback i 11. Themethod-of preventing undue contraction of the molten backings ofelectrotypes during cooling of the same which consists in restrainingmovement of the congealing backing of the molten metal, effecting therestraint at intervals along the surface of the backing.

12. The method of preventing undue contraction of the molten backings ofelectrotypes during cooling of the same which consists in pressingagainst the back surface thereof a holding member having a smaller totalcontraction through the ranges of cooling represented than that of thebacking metal. y

13. The method of preventing undue contraction of the molten backings ofelectrotypes during cooling of the same which consists in holding theouter surface of the backing metal by a grid of solid material.

14. The method of preventing undue contraction of the molten backings ofelectrotypes during cooling of the same which consists in backing theelectrotype within a holder of molten metal, frictionally engaging thetop of the backing with considerable pressure and striking the face ofthe holder progressively with respect to the surface of the holder.

15. The method of relieving molten backing metal of trapped air whichconsists in impressing upon the back ofthe metal a grid of solidmaterial and subsequently Ajarring the faite of the electrotype byimpulses from the face side thereof.

16. The method of backing electrotypes which consists in supplying -theelectrotype in a suitable holder with a molten backing adapted to adhereto the back surface of the adapted to ladhere to the back surface of theelectrotype, restraining undue contraction of electrotype, restrainingundue contraction of :the lipper part of the backing material and theupper part of the hacking material and 10 rapping the holder. rappingthe holder progressively overrits 17. TheV method of backingeleotrotypes surface.

which Consists in supplying the eleotrotype l in a suitable holder Wit-ha molten backing f HARRY M. BLAETZ.

